Sometimes when relating 2 entities, it could be very powerful to attach metadata to the relation itself. Suppose the attached data model, where we model Packages and Package Versions. We want Package Versions to list their dependencies, but they can't point to specific other versions, because they probably use semver ranges (e.g. ^1.2.3), so we instead link them only to the Package, loosing version information. I would love if on the Package Dependency relation I could add "SemVer Range" as a property, such that each edge would have that data.